In praise of the humble DVD

 

Most computer users are now conversant about SSDs, multi-terabyte drives, Dropbox, iCloud, Google Drive and a host of other backup mediums, however most seem to have forgotten about the simplicity and the reliability of the humble DVD.

Let’s say you have irreplaceable photos or video files of your first born, your round-the-world trip or of a loved one who has shuffled off this mortal coil. Where will you store these photos so in twenty years’ time they will still be intact?  Would you really trust iCloud or Google Drive with these? Maybe. But the reality is that cloud-based storage services are prone to hacking, sabotage and in some instances have been known to corrupt or simply lose data altogether. More worryingly, you have to ask: will these cloud storage providers even be around in twenty years’ time?

There is of course the option of storing your photos on a mechanical hard drive in the hope that in twenty years’ time when connected to your computer (probably via some USB-to-god-knows-what adaptor), it will spin into life (for those familiar with mechanical hard drives… stop sniggering) It might do that – but the risk that you will be greeted with clicking noises or no noises at all are too high.

Or, you could put your data onto an SSD (solid state drive). They have no mechanical parts and storing all your photos or videos on one of these is a much safer bet right? Not exactly because if you have an SSD drive which you stash in a drawer (cupboard, attic, etc.) for a number of years it will eventually start to lose its charge in the same way that a battery loses charge over time. This can have grave repercussions for your data as it is stored using quantum electron tunnelling which is reliant on stored positive and negative electrical charges. Error correction codes such as the Bose-Chaudhuri-Hocquenghem algorithm can be very effective in rewriting failed cells, but there comes a point where the errors become so pervasive that drive becomes unreadable. SSD manufacturers know about this phenomenon, but don’t explicitly state it in their documentation. Maybe buried deep in the small print, they might recommend that their SSD drives are to be used on host devices “periodically” or “at regular intervals”. This basically translates into “if you don’t use your SSD drive regularly, you’re going to lose your data”. Great.

There are of course disk mirroring devices (such as a DAS or NAS) which can be used to replicate your data over two or more disks (mechanical or SSD). While these do lower the risk of data loss – these devices are still subject to same failure factors as standalone disks.

This leaves us with the humble DVD. It is compact, non-magnetic, does not need to be “recharged” and is cost-effective.  For the long-term storage of photos, video footage or documents, it ticks a lot of boxes.

If your laptop or desktop computer did not come equipped with a DVD burner, an external USB DVD drive can be used. The actual recording takes place on the dye layer of the disk which is permanently altered by a highly focused laser beam. The DVD burning process can be tedious but it is time well spent if your data is in any way important to you. The main variants of DVD disk are DVD-RAM, DVD-R, DVD-RW, DVD+R and DVD+RW. For long-term storage, DVD-R has the best compatibility.  These are usually available in capacities of 4.7GB and 8.5GB. Many archival specialists working for state archive departments and archive departments of broadcasters swear by the Taiyo Yuden brand (a Japanese company whose blank DVD’s are also marketed under the JVC and “That’s” brand).  Verbatim also makes their UltraLife Gold Archival Grade DVD-R which are specifically designed for long-term storage are also well respected by archivists.

So, the next time you need to perform a backup of really important files which you would like to access in twenty years’ time, don’t forget about the DVD. When mechanical and SSD disks have long since failed and storage clouds have evaporated, the humble DVD will probably be the last man standing.

Drive Rescue Data Recovery is based in Dublin, Ireland. We recover data from external and internal hard drives (SSD and mechanical), servers, NAS devices and USB memory sticks. Brands we frequently work with include WD, Toshiba, Seagate and HGST disks. Our customers hail from the four corners of Ireland, including Dublin, Cork, Limerick, Galway, Waterford and Kilkenny.

Data recovery from Buffalo Terastation RAID 5 (XFS file system)

buffalo-nas-data-recovery-ireland

 

 

We recently helped a Dublin medical practice recover data from their failed Buffalo Terastation RAID 5 NAS device.

It was being used as a file server between four workstations in their office. One month previously, they had noticed that something might be awry when their NAS started to display error codes its LCD. But as their NAS continued to function, they did not give the error codes much heed. Then last week, their NAS became inaccessible altogether.

Diagnosis

We opened up their Terastation device. Inside we found 4 X 1TB Western Digital WD10EFRX-68PJCN0 NASware “Red” disks. We removed them from their bays and attached them to our recovery system. We discovered they were configured in RAID 5 (using a block size of 256KB) and the array was using the XFS file system. We performed diagnosis on each disk. Disk “0” had a problem with head “3” and disk “3” had extensive bad sectors. Disks “1” and “2” tested fine.

Data recovery solution

We would work with disks “1”,”2” and “3” to rebuild the array. We imaged all of these disks so we would be working with copies and not the originals. We now had the challenge of rebuilding the XFS volume. This took a few hours to manually reconstruct with the aid of a HEX editor. Eventually we had a mountable volume again but still no files were visible. This is quite normal after a reconstruction of an XFS array as there is a high probability that some allocation group header structures will still be “out of place” or some missing inode clusters may still exist. These needed to be rebuilt or corrected using XFS repair commands.

Files found

Once the volume’s files appeared, it was now time to extract them onto a 4TB external USB drive. Most of the files were .DICOM files (x-ray images, all of which were intact) which the client was very pleased to see again.

Beware of “warning fatigue”

Reflecting on this case, the client made two mistakes which eventually led to a data loss situation. Firstly, they had mistaken a file server for a back-up device. They believed that because it was a NAS device, it could not fail on them. This is a common misconception that users have about NAS devices. While they certainly do have a lower probability of suddenly and catastrophically failing, they can still fail, albeit slowly and with more warning than a standalone disk. But, in this case, they did not heed to the warning, namely the “I12” error message which they saw appear on the Buffalo’s LCD”. This is understandable.  The average user is getting bombarded with warning messages about everything from their media player software being out-of-date to low-ink warning messages from their printer.  When it comes to really important messages from, for example, back-up hardware or software, these can get “downgraded” in a user’s mind to “just another error message”.  System administrators or IT support technicians have an important role to play in delineating to users the importance of acting on any messages relating to data backup. Hardware manufacturers also have a role in making their error messages on their devices less cryptic and more comprehensible for your “average” user. For example, Buffalo’s “I12” code to signify it’s RAID is operating in degraded mode means very little to the average user. A more succinct message such as “array failing” might spur a whole lot more users into action and help them avoid the costs of data recovery!